Biometrics is the science of identifying humans based on their physical, behavioral or psycho-physiological characteristics [1]}, with one assumption being that such characteristics are unique. Uniqueness refers to the ability of a biometric modality to distinguish between individuals, indicating how a biometric characteristic varies across the population. Consequently, an individual possesses high biometric uniqueness, if the distance distribution of their genuine (mated) comparison scores is well separated from the distance distribution of impostor (non-mated) comparison scores. Hence, an individual is less unique if their genuine and impostor distributions significantly overlap (see Figure REF ). We note that while a similarity match score represents a genuine score if it is a result of matching two biometric samples of the same individual, an impostor score refers to comparing of two biometric samples originating from different individuals [2]}.
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